I know that ideal thing is to use concrete, a mix of cement and aggregate (usually sand and gravel/rocks. However I have a bag of cement that's not going to go to any use, and my aim is just to cover a hole or channel that exists between concrete ground and a fence. The channel is only about 15 cm (6 inches) wide and will most likely not have any weight placed on it. The channel is about half a foot deep, so what I thought of doing is to fill the channel as high as possible with dirt and rocks, and then mix up cement with water just to smoothly cover the surface.
My main aim here is to basically plug the gap were things can fall between the fence and concrete ground, such as rubbish. Will cement and water be satisfactory for this job? I don't have any sand, but I can (if it's advisable) try to mix up some small rocks with the cement, so that the mix will basically be 1 part gravel to one part cement. Or do I even need the gravel? As I said, I'm just trying to plug a hole/channel in the ground, and I intend to fill most of it with medium sized rocks before I apply the cement anyway.
I don't know much about concrete/cement/aggregate. I only know that the cement by itself is useless in most applications because the strength comes from the aggregate, not the cement, which I understand is just a binder. However in this case where I'm just plugging a gap I'm wondering if this is OK.